.Net MinimalApis响应返回值的详细过程

前言

本文主要讲MinimalApis中的使用自定义IResultModel和系统自带IResult做响应返回值。MinimalApis支持以下类型的返回值：

string- 这包括Task<string>和ValueTask<string>
T（任何其他类型）- 这包括Task<T>和ValueTask<T>
基于IResult- 这包括Task<IResult>和ValueTask<IResult>

本文的完整源代码在文末

string返回值

行为Content-Type框架将字符串直接写入响应。text/plain

200状态代码与text/plainContent-Type标头和以下内容一起返回

Hello World

T（任何其他类型）返回值

我们上面说的自定义 IResultModel就是用这种模式处理的

行为Content-Type框架 JSON 序列化响应。application/json

MinimalApis框架Json序列化全局配置如下

//通过调用 ConfigureHttpJsonOptions 来全局配置应用的选项
builder.Services.ConfigureHttpJsonOptions(options =>
{
options.SerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;//忽略循环引用
options.SerializerOptions.WriteIndented = true;
options.SerializerOptions.IncludeFields = true;
options.SerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
});

返回 T

app.MapGet(\”/TestT\”, User () => new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 })
.WithSummary(\”测试类\”)
.Produces<User>();

返回值

{
\”name\”: \”Ruipeng\”,
\”email\”: \”xxx@163.com\”,
\”age\”: 18
}

200状态代码与application/jsonContent-Type标头和以下内容一起返回

这个HttpCode状态码只能返回200，且不支持多种返回形式，比较局限

统一响应格式代码

public interface IResultModel
{
/// <summary>
/// 是否成功
/// </summary>
bool? IsSuccess { get; }
/// <summary>
/// 错误信息
/// </summary>
string? Message { get; }
/// <summary>
/// 业务码，用于业务中自定义
/// </summary>
int? StatusCode { get; set; }
/// <summary>
/// 时间戳
/// </summary>
long? Timestamp { get; }
}
/// <summary>
/// 返回结果模型泛型接口
/// </summary>
/// <typeparam name=\”T\”></typeparam>
public interface IResultModel<out T> : IResultModel
{
/// <summary>
/// 返回数据
/// </summary>
T? Data { get; }
}

实现

public class ResultModel<T> : IResultModel<T>
{
public ResultModel()
{
Timestamp = DateTimeOffset.Now.ToUnixTimeSeconds();
}
/// <summary>
/// 处理是否成功
/// </summary>
public bool? IsSuccess { get; set; }
/// <summary>
/// 错误信息
/// </summary>
public string? Message { get; set; }
/// <summary>
/// 业务码
/// </summary>
public int? StatusCode { get; set; }
/// <summary>
/// 时间戳
/// </summary>
public long? Timestamp { get; }
/// <summary>
/// 返回数据
/// </summary>
public T? Data { get; set; }
/// <summary>
/// 成功
/// </summary>
/// <param name=\”Data\”></param>
public ResultModel<T> Success(T? data = default)
{
this.IsSuccess = true;
StatusCode = 200;
Data = data;
return this;
}
/// <summary>
/// 失败
/// </summary>
/// <param name=\”msg\”>说明</param>
/// <param name=\”code\”></param>
public ResultModel<T> Failed(string? msg = \”failed\”, int? code = 500)
{
IsSuccess = false;
Message = msg;
StatusCode = code;
return this;
}
}
/// <summary>
/// 返回结果
/// </summary>
public static class ResultModel
{
/// <summary>
/// 数据已存在
/// </summary>
/// <returns></returns>
public static IResultModel<string> HasExists => Failed(\”data already exists\”);
/// <summary>
/// 数据不存在
/// </summary>
public static IResultModel<string> NotExists => Failed(\”data doesn\’t exist\”);
/// <summary>
/// 成功
/// </summary>
/// <param name=\”data\”>返回数据</param>
/// <returns></returns>
public static IResultModel<T> Success<T>(T? data = default)
{
return new ResultModel<T>().Success(data);
}
/// <summary>
/// 成功
/// </summary>
/// <param name=\”task\”>任务</param>
/// <returns></returns>
public static async Task<IResultModel<T>> SuccessAsync<T>(Task<T>? task = default)
{
return task is not null && task != default ? new ResultModel<T>().Success(await task) : new ResultModel<T>();
}
/// <summary>
/// 成功
/// </summary>
/// <returns></returns>
public static IResultModel<string> Success()
{
return Success<string>();
}
/// <summary>
/// 失败
/// </summary>
/// <param name=\”error\”>错误信息</param>
/// <returns></returns>
public static IResultModel<T> Failed<T>(string? error = null)
{
return new ResultModel<T>().Failed(error ?? \”failed\”);
}
/// <summary>
/// 失败
/// </summary>
/// <returns></returns>
public static IResultModel<string> Failed(string? error = null)
{
return Failed<string>(error);
}
/// <summary>
/// 根据布尔值返回结果
/// </summary>
/// <param name=\”success\”></param>
/// <returns></returns>
public static IResultModel<T> Result<T>(bool success)
{
return success ? Success<T>() : Failed<T>();
}
/// <summary>
/// 根据布尔值返回结果
/// </summary>
/// <param name=\”success\”></param>
/// <returns></returns>
public static async Task<IResultModel> Result(Task<bool> success)
{
return await success ? Success() : Failed();
}
/// <summary>
/// 根据布尔值返回结果
/// </summary>
/// <param name=\”success\”></param>
/// <returns></returns>
public static IResultModel<string> Result(bool success)
{
return success ? Success() : Failed();
}
/// <summary>
/// 时间戳起始日期
/// </summary>
public static readonly DateTime TimestampStart = new(1970, 1, 1, 0, 0, 0, 0);
}

定义接口

app.MapGet(\”/TestResultModel\”, IResultModel (int age) =>
{
List<User> users = [new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }];
return users.FirstOrDefault(_ => _.Age > age) is User user ? ResultModel.Success(user) : ResultModel.Failed();
})
.WithSummary(\”测试自定义IResultModel\”)
.Produces<IResultModel<User>>();

封装了一个静态类来简化自定义类的创建，支持多个返回类型

返回值

{
\”isSuccess\”: true,
\”statusCode\”: 200,
\”timestamp\”: 1711001093,
\”data\”: {
\”name\”: \”Ruipeng\”,
\”email\”: \”xxx@163.com\”,
\”age\”: 18
}

自定义类的自动包装实现

创建一个Attribute

[AttributeUsage(AttributeTargets.Method)]
public class EnableResponseWrapperAttribute : Attribute { }

创建中间件自动包装

public class ResponseWrapperMiddleware(RequestDelegate next)
{
public async Task InvokeAsync(HttpContext context)
{
if (context.GetEndpoint()?.Metadata.GetMetadata<EnableResponseWrapperAttribute>() is not null)
{
// 存储原始响应体流
var originalResponseBodyStream = context.Response.Body;
try
{
// 创建内存流以捕获响应
using var memoryStream = new MemoryStream();
context.Response.Body = memoryStream;
// 调用管道中的下一个中间件
await next(context);
// 恢复原始响应体流并写入格式化结果
context.Response.Body = originalResponseBodyStream;
// 重置内存流位置并读取响应内容
memoryStream.Seek(0, SeekOrigin.Begin);
var readToEnd = await new StreamReader(memoryStream).ReadToEndAsync();
var objResult = JsonSerializer.Deserialize<dynamic>(readToEnd);
var result = new ResultModel<object>
{
Data = objResult,
IsSuccess = true,
StatusCode = context.Response.StatusCode
};
await context.Response.WriteAsJsonAsync(result as object);
}
finally
{
// 确保在出现异常时恢复原始响应体流
context.Response.Body = originalResponseBodyStream;
}
}
else
{
await next(context);
}
}
}

应用中间件

app.UseMiddleware<ResponseWrapperMiddleware>();

创建测试接口

app.MapGet(\”/TestTestAutoWarpper\”, [EnableResponseWrapper] User () => new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }).WithSummary(\”测试类\”)
.Produces<User>();

返回值

{
\”isSuccess\”: true,
\”statusCode\”: 200,
\”timestamp\”: 1711005201,
\”data\”: {
\”name\”: \”Ruipeng\”,
\”email\”: \”xxx@163.com\”,
\”age\”: 18
}
}

为了方便测试在MinimalApis的接口上如果添加了EnableResponseWrapperAttribute则通过中间件自动包装返回值

IResult 返回值

行为Content-Type框架调用 IResult.ExecuteAsync由 IResult 实现决定

在dotNet7之后多了一个TypedResults类来替代Results。IResult接口定义一个表示HTTP终结点结果的协定。静态Results类和静态TypedResults用于创建表示不同类型的响应的各种IResult对象。

返回 TypedResults（而不是 Results）有以下优点：

TypedResults帮助程序返回强类型对象，这可以提高代码可读性、改进单元测试并减少运行时错误的可能性。
实现类型会自动为OpenAPI提供响应类型元数据来描述终结点。实现在Microsoft.AspNetCore.Http.HttpResults

//Return IResult
app.MapGet(\”/IResult/TestResult\”, IResult () => Results.Ok(new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }));

没有调用扩展方法Produces

app.MapGet(\”/IResult/TestTypedResult\”, IResult () => TypedResults.Ok(new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }));

可以看到 TypedResults 默认就会添加路由终结点的元数据描述

返回多个 IResult 实现类型

app.MapGet(\”/IResult/ReturnMultipleTypes\”, Results<Ok<User>, NotFound> (int age) =>
{
List<User> users = [new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }];
return users.FirstOrDefault(_ => _.Age > age) is User user ? TypedResults.Ok(user) : TypedResults.NotFound();
});

图简单可以直接用IResult返回类型但是，由于TypedResults帮助程序自动包含终结点的元数据，因此可以改为返回Results<Ok<User>, NotFound>联合类型

IResult 自定义响应

添加 Html 扩展

public static class ResultsExtensions
{
public static IResult Html(this IResultExtensions resultExtensions, string html)
{
ArgumentNullException.ThrowIfNull(resultExtensions);
return new HtmlResult(html);
}
}
class HtmlResult(string html) : IResult
{
private readonly string _html = html;
public Task ExecuteAsync(HttpContext httpContext)
{
httpContext.Response.ContentType = MediaTypeNames.Text.Html;
httpContext.Response.ContentLength = Encoding.UTF8.GetByteCount(_html);
return httpContext.Response.WriteAsync(_html);
}
}
app.MapGet(\”/IResult/Html\”, () => Results.Extensions.Html(@$\”<!doctype html>
<html>
<head><title>miniHTML</title></head>
<body>
<h1>Hello World</h1>
<p>The time on the server is {DateTime.Now:O}</p>
</body>
</html>\”));

返回结果

<!DOCTYPE html>
<html>
<head>
<title>miniHTML</title>
</head>
<body>
<h1>Hello World</h1>
<p>The time on the server is 2024-03-21T17:31:36.2931959+08:00</p>
</body>
</html>

自定义 Json 格式

上面写了ConfigureHttpJsonOptions方法来配置全局请求的 Json 格式，下面则是针对单个路由终结点请求，方便一些个性化接口的处理

var options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
{ WriteIndented = true };
app.MapGet(\”/IResult/CustomJsonConfig\”, () =>
TypedResults.Json(new User() { Name = \”Ruipeng\”, Email = \”xxx@163.com\”, Age = 18 }, options));

返回 ProblemDetail

app.MapGet(\”/IResult/ProblemDetail\”, () =>
{
var problemDetail = new ProblemDetails()
{
Status = StatusCodes.Status500InternalServerError,
Title = \”内部错误\”
};
return TypedResults.Problem(problemDetail);
});

返回值

{
\”type\”: \”https://tools.ietf.org/html/rfc9110#section-15.6.1\”,
\”title\”: \”内部错误\”,
\”status\”: 500
}

在Microsoft.AspNetCore.Http.Results的扩展下，TypedResults 有非常多扩展的方法，比如处理文件，回调，流以及登录认证等，大家可以根据需求使用.